Cloning and expression of the human galanin receptor GalR2.
Galanin is a peptide hormone which modulates a wide variety of physiological processes, including secretion, muscle contraction, cognitive function, the reproductive axis, and feeding. Two galanin receptor subtypes, GalR1 and GalR2, have been cloned; however, for GalR2 only the rat sequence has been reported in the literature. Our cloning of human GalR2 reveals its amino acid sequence to be 85% identical to rat GalR2 and 39% identical to human GalR1. Binding of [125I]galanin to the human GalR2 receptor transiently expressed in COS-7 cells was saturable (Kd = 0.24 nM +/- 0.06 nM) with a receptor density of 383 +/- 66 fmol/mg protein. Human galanin(1-30) bound with high affinity to the human GalR2 receptor, with a Ki value of 0.86 +/- 0.12 nM. With the identification of a second galanin receptor subtype, the specific functions of human galanin receptor subtypes can now begin to be addressed.
Bloomquist
B T
BT
Institute for Metabolic Disorders, Bayer Corporation, West Haven, Connecticut 06516, USA. btb@wh.bayer.com
Beauchamp
M R
MR
Zhelnin
L
L
Brown
S E
SE
Gore-Willse
A R
AR
Gregor
P
P
Cornfield
L J
LJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D003001:Cloning, Molecular; D019004:Galanin / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone / Q000737:chemistry* / Q000145:classification; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014162:Transfection / Q000235:genetics
D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D012333:RNA, Messenger; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone; D019004:Galanin